The present invention relates to a needle selector for a knitting machine and, more particularly, to a needle selection finger formed by combining a plurality of members, and a needle selector for a knitting machine which uses it.
In a knitting machine such as a circular knitting machine or weft knitting machine, vertical motions of the working needle are selected on the basis of a knitting procedure stored in a storage such as a floppy disk, to knit a fabric of a desired knit texture. Various types of needle selectors are used for selecting the vertical motions of the working needle.
Before describing the needle selector according to the present invention, the outline of needle selection in a knitting machine will be explained with reference to a circular knitting machine schematically illustrated in FIGS. 4A to 4C.
FIG. 4A is a schematic perspective view for explaining the basic knitting mechanism of a circular knitting machine. As illustrated in FIG. 4A, the circular knitting machine has a knitting cylinder 1 rotatable in the direction indicated by an arrow A. A plurality of vertical grooves (not shown) are formed in the outer surface of the knitting cylinder 1 along its longitudinal axis. Working needles 2 are arranged slidably in the vertical grooves. Usually, needle selection jacks 12 are arranged under the working needles 2 to be able to abut against the lower parts of the working needles 2. A cylinder-shaped cam base 15a is stationarily arranged under the knitting cylinder 1. A plurality of raising cams 15 with predetermined shapes are arranged on the upper part of the cam base 15a at predetermined intervals.
The basic principle of knitting will be briefly described. When each working needle 2 on the rotating knitting cylinder 1 is thrust upward by the corresponding raising cam 15 through the needle selection jack 12, it projects from the upper surface of the knitting cylinder 1. A yarn 5 fed from a yarn bobbin 6 is supplied to the hook of the projecting working needle 2, thus forming a yarn loop. Then, the working needle 2 is lowered by a known mechanism (not shown), so one stitch is formed. Therefore, control operation of forming a stitch by selecting whether vertical motion is to be applied to the working needle 2, or allowing advance to the next knitting step without forming a stitch can be performed. As a result, a desired fabric can be knitted. In order to provide such motions to the working needles, in the knitting machine, the needle selection jacks 12 are usually arranged in contact with the lower parts of the working needles 2. The vertical motions of the working needles are controlled, by selectively engaging the needle selection jacks 12 and raising cams 15, by using a needle selector 3, operating on the basis of information from a controller 4 with a built-in storage that stores a knitting procedure.
Next, a case wherein piezoelectric bodies are used as needle selection means will be described with reference to FIGS. 4B and 4C which show the relationship among the working needles 2, needle selection jacks 12, and needle selector 3. FIGS. 4B and 4C are schematic views that facilitate understanding of the operation of the needle selection means with ease.
A piezoelectric body 7 can be either curved as shown in FIG. 4B, or curved as shown in FIG. 4C, in the direction opposite to that shown in FIG. 4B, depending on how a voltage is applied to it. A finger 9 is arranged at the tip of the piezoelectric body 7 to be linked to it. In FIGS. 4B and 4C, the piezoelectric body 7, finger 9, and raising cam 15 are positioned within the surface of the drawing, and the working needle 2 and needle selection jack 12 move circularly together with the knitting cylinder 1 (not shown) from the top to the bottom of the surface of the drawing (or in the reverse direction). The needle selection jack 12 can swing about a fulcrum 12a as the center. A needle selection butt 13 (upper part) and raising cam butt 14 (lower part) project sideways from the needle selection jack 12 as shown in FIGS. 4B and 4C.
When the piezoelectric body 7 is curved as shown in FIG. 4B, the needle selection butt 13 of the needle selection jack 12 which moves circularly hits the finger 9. As a result, the needle selection jack 12 is thrust clockwise about the fulcrum 12a as the center, and the raising cam butt 14 of the needle selection jack 12 cannot engage with the raising cam 15. Therefore, the needle selection jack 12 is not thrust upward by the raising cam 15, and accordingly the working needle 2 is not thrust upward.
When the piezoelectric body 7 is curved as shown in FIG. 4C, the finger 9 at its tip does not hit the needle selection butt 13 of the needle selection jack 12 which moves circularly together with the knitting cylinder 1. Hence, the needle selection jack 12 remains in the vertical direction, and accordingly the raising cam butt 14 at the lower end of the needle selection jack 12 engages with the raising cam 15. Therefore, the needle selection jack 12 is thrust upward along the inclined surface of the raising cam 15, and accordingly the working needle 2 is also thrust upward.
A member indicated by reference numeral 25 in FIGS. 4B and 4C is a finger pivot stopper formed by part of the frame of the needle selector. When the position of the member 25 is appropriately determined, the finger 9 engages with the needle selection butt 13 reliably, so the finger 9 is prevented from drifting over contact with the needle selection butt 13.
In this manner, selective engagement of the needle selection butt 13 of the needle selection jack 12 with the finger 9 at the tip of the piezoelectric body 7 enables the working needle 2 to move upward freely as desired and thereby enables a knit fabric of any desired knit texture to be knit.
FIG. 5 shows the relationship between the piezoelectric body 7 and finger 9 of this piezoelectric needle selector 3.
As shown in FIG. 5, the finger 9 is arranged to be movable relative to the piezoelectric body 7 having a bimorph piezoelectric element. Power is applied to the piezoelectric body 7 to actuate the finger 9. This motion of the finger 9 causes the working needles of the knitting machine to be selected (more specifically, via the needle selection jack 12), and knitting of a fabric with a predetermined knit texture is made possible. The rear end of the piezoelectric body 7 is movably supported via a spherical body, i.e., a rotary body 20, by a support 21 or a concave part 22 of a housing. The tip of the piezoelectric body 7 is movably linked via a rotary body 16 into a U-shaped groove 17 (to be referred to as a slit 17 hereinafter) at the rear end of the finger 9. The piezoelectric body 7 is arranged with its predetermined position between the rear end and the tip of the piezoelectric body 7 being pinched by a rotary body 23 rotatably fitted to a support 24 or the housing.
As shown in FIG. 5, the finger 9 is supported at its intermediate portion 9b by a support 10b through a pin 18. Hence, when the piezoelectric body 7 flexes, its motion vertically moves a rear end (piezoelectric body engaging portion) 9a of the finger 9. As a result, the finger 9 swings about the pin 18, serving as the pivot support point of the finger 9, as the center, so a bar-shaped portion 9C of the finger 9 projecting through an opening 11 of a support 10a swings, and consequently a tip 9d moves vertically. The vertical motion of the tip 9d causes the rising motion of the working needle 2 described above to be selected.
FIG. 6A is a side view of a conventionally known finger 9, and FIG. 6B is a front view of the same. As shown in FIGS. 6A and 6B, the finger 9 is comprised of a bar-shaped thin elongated member 9c extending from a butt abutting surface 9d at its tip to reach a central portion 9b having a pivot support point 18a, and a piezoelectric body engaging portion 9a extending from the central portion 9b in the other direction. The pivot support point 18a is on a longitudinal axis 9X1 of the bar-like thin elongated member. The piezoelectric body engaging portion 9a has a slit 17 to accommodate a curved motion end 16 of the piezoelectric body.
As shown in FIGS. 6A and 6B, the conventionally known finger 9 is formed of a material, integral from its butt abutting surface 9d on the knitting cylinder-side tip to the piezoelectric body engaging portion 9a of the needle selector.
The shape, size, and the like of the finger 9, however, change depending on the type of the knitting machine, the type of the needle selector, and the knit texture of the fabric to be knitted by this knitting machine. The manufacturer of the needle selector for the knitting machine copes with this situation by preparing very many types of fingers in stock.
In view of this, it has been discussed to form a predetermined finger in the following manner. The operatively downstream portions (to be referred to as finger members in the following description) of fingers which have butt abutting surfaces engageable with the needle selection jacks of the knitting cylinder and the operatively upstream portions (to be referred to as finger holding members in the following description) of the fingers which have the piezoelectric body engaging portions for the needle selector are fabricated by separate manufacturing steps, and are kept in stock. A finger holding member and finger member are appropriately selected and combined in accordance with the type of the knitting machine in which the finger is to be used, and with the knit texture of the target fabric, thus forming the predetermined finger. This can greatly reduce the number of the types of fingers to be kept in stock.
A finger (to be referred to as a module finger hereinafter) which is formed by combining a finger holding member and finger member to match the object is recently known. An example of the module finger will be described hereinafter with reference to FIGS. 7A and 7B showing perspective views.
A module finger 30a shown in FIG. 7A is comprised of a finger member 31a and finger holding member 40a. The finger member 31a is comprised of a butt abutting portion 33a having a butt abutting surface 32a at its tip, and a support 34a extending like a bar from the butt abutting portion 33a. The finger holding member 40a has a metal plate slit 44a at its lower part to form a piezoelectric body engaging portion 45a. A connecting plate 46 is connected to the upper side of the slit 44a. 
The finger member 31a and finger holding member 40a of the module finger 30a shown in FIG. 7A are connected using a synthetic resin after the lower part of the support 34a of the finger member 31a and the connecting plate 46 above the finger holding member 40a are manually arranged to oppose each other. Namely, a connecting portion 51 is formed from the synthetic resin.
The module finger 30a obtained with this method cannot be used for high-speed rotation, since the positional relationship between the butt abutting surface 32a and piezoelectric body engaging portion 45a is low. Furthermore, the complicated manual operation using the synthetic resin increases the cost.
A module finger 30b shown in FIG. 7B is comprised of a metal finger member 31b substantially identical with the finger member 31a shown in FIG. 7A, and a synthetic resin finger holding member 40b. The module finger shown in FIG. 7B is manufactured in the following manner. More specifically, first, the finger member 31b is manufactured with high precision by using a metal material, and is kept in stock. When fabricating a specific module finger 30b, a finger member 31b with a structure suitable for the knit texture of the fabric is selected. A mold corresponding to the structure of the target finger holding member 40b is loaded in an injection molder, and the finger member 31b is arranged at a predetermined position in the mold of the injection molder. Then, a synthetic resin is injected.
The module finger 30b shown in FIG. 7B, which is obtained in accordance with the above method, has excellent size precision. Regarding the manufacture of the module finger 30b, the expensive injection molder must be operated by a skilled operator. This increases the cost of the obtained module finger.
Although a demand for a module finger with which the stock of the fingers can be decreased and which can be manufactured to meet the situation has arisen, such a module finger is substantially difficult to become popular.
It is an object of the present invention to solve the problems of the conventionally known module finger and to provide a new module finger with which fingers that need to have various types of shapes can be supplied quickly as required at a low cost.
In order to achieve the above object, a needle selector for a knitting machine according to the present invention has the following arrangement.
More specifically, there is provided a needle selector for a knitting machine, in which a plurality of needle selection jacks each having at least one butt projecting therefrom are swingably fitted in a plurality of vertical grooves in an outer surface of a knitting cylinder such that working needles in contact with the jacks move vertically, characterized in that
the needle selector comprises a module finger for selectively engaging with the needle selection jacks of the knitting machine so as to swing the needle selection jacks, and a driving member for pivoting the module finger on the basis of a predetermined knitting procedure,
the module finger having
a finger member having a butt abutting portion with a butt abutting surface at a tip thereof, and a support extending from the butt abutting portion, and
a finger holding member having a connecting portion, at one end thereof, where part of the support of the finger member is mounted so the finger member can be positioned, an engaging portion, at the other end thereof, to be engageable with the driving member of the needle selector for the knitting machine, and a pivot support arranged between the two ends to provide a module finger pivot support point, and
the finger member and said finger holding member being combined to each other so that a positioning state obtained by mounting part of the support of the finger member on the connecting portion of the finger holding member is maintained.
A needle selection module finger according to the present invention for achieving the above object has the following arrangement.
More specifically, there is provided a needle selection module finger for a needle selector for a knitting machine, which comprises a finger member and a finger holding member,
wherein the finger member has a butt abutting portion with a butt abutting surface at a tip thereof, and a support extending from the butt abutting portion,
the finger holding member has a connecting portion, at one end thereof, where part of the support of the finger member is mounted so the finger member can be positioned, and an engaging portion, at the other end thereof, to be engageable with a driving member of the needle selector for the knitting machine, and
the module finger further comprises
combining means for combining the finger member and the finger holding member to each other so that a positioning state obtained by mounting part of the support of the finger member on the connecting portion of the finger holding member is maintained.
Furthermore, a method of manufacturing a needle selection module finger according to the present invention for achieving the above object comprises the steps of
manufacturing a finger member having a butt abutting portion with a butt abutting surface at a tip thereof, and a support extending from the butt abutting portion,
manufacturing a finger holding member having a connecting portion, at one end thereof, where part of the support of the finger member is mounted so the finger member can be positioned, and an engaging portion, at the other end thereof, to be engageable with a driving member of a needle selector for a knitting machine, and
positioning the finger member and the finger holding member by mounting part of the support of the finger member on the connecting portion of the finger holding member, and combining the finger member and the finger holding member such that a positioning state thereof is maintained.
The needle selection module finger having the above arrangements according to the present invention can be used in various types of needle selectors for a knitting machine.